rishi/scryer-prolog
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remove Addr::PStrTail (#276)

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This commit is contained in:
Mark Thom
2020-03-17 02:03:29 -06:00
parent f9c4a40d60
commit b1d8eff019
11 changed files with 181 additions and 431 deletions
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56
src/prolog/machine/heap.rs
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@@ -152,32 +152,23 @@ impl<T: RawBlockTraits> HeapTemplate<T> {
pub(crate)
fn allocate_pstr(&mut self, mut src: &str) -> Option<Addr> {
let orig_h = self.h();
loop {
if src == "" {
return if orig_h == self.h() {
None
} else {
let prev_h = self.h() - 1;
match &mut self[prev_h] {
HeapCellValue::PartialString(ref mut pstr) => {
let s = pstr.block_as_str();
pstr.tail = Addr::PStrTail(prev_h, s.len());
}
_ => {
unreachable!()
}
}
let tail_h = self.h() - 1;
self[tail_h] = HeapCellValue::Addr(Addr::HeapCell(tail_h));
Some(Addr::PStrLocation(orig_h, 0))
};
}
let h = self.h();
let (mut pstr, rest_src) =
match PartialString::new(src, h) {
let (pstr, rest_src) =
match PartialString::new(src) {
Some(tuple) => {
tuple
}
@@ -188,46 +179,21 @@ impl<T: RawBlockTraits> HeapTemplate<T> {
} else if orig_h == h {
return None;
} else {
let prev_h = h - 1;
match &mut self[prev_h] {
HeapCellValue::PartialString(ref mut pstr) => {
let s = pstr.block_as_str();
pstr.tail = Addr::PStrTail(prev_h, s.len());
}
_ => {
unreachable!()
}
}
self[h - 1] = HeapCellValue::Addr(Addr::HeapCell(h - 1));
return Some(Addr::PStrLocation(orig_h, 0));
}
}
};
let new_top = unsafe {
self.buf.new_block(mem::size_of::<HeapCellValue>())
};
self.push(HeapCellValue::PartialString(pstr));
if rest_src != "" {
pstr.tail = Addr::PStrLocation(h+1, 0);
self.push(HeapCellValue::Addr(Addr::PStrLocation(h + 2, 0)));
src = rest_src;
} else {
pstr.tail = Addr::PStrTail(h, src.len());
}
unsafe{
ptr::write(
self.buf.top as *mut _,
HeapCellValue::PartialString(pstr),
);
}
self.buf.top = new_top;
if rest_src == "" {
self.push(HeapCellValue::Addr(Addr::HeapCell(h + 1)));
return Some(Addr::PStrLocation(orig_h, 0));
}
}
}
}